18th Street in Zone 1 is the city's main bus transfer point, which makes it one of the only places in town with round-the-clock activity. In addition to hundreds of buses, the traffic brings lots of markets and street food - about 6 blocks of semi-covered stalls and countless booths and sidewalk operations on the side streets nearby.

I took this particular photo to try to capture the cloud of black smoke that had just been belched on the people standing next to the bus. However the camera seems to have done an environmental clean-up job on it. I promise, in real life it was so thick you could have captured it in a bag.